I've participated in quite a few different sized tournaments, and ran the gamut on types of schedules encountered.
2007 was a disaster. The basis of the scheduling algorithm was that it divided teams into three "bins" based on team number (lowest third, middle third, and upper third). Each alliance contained one member from each bin. As far as I recall, this was done by the algorithm maker without the solicitation of FIRST HQ. There were improvements made to the system as the season progressed, but the concept was fundamentally flawed.
In 2007 week one, the system was impossibly bad. If you study team
116's schedule from VCU you'll begin to see why. Because VCU had 66 teams, a number divisible by 6 (the quantity of teams in each match), VCU ended up with a very rigid schedule. The teams in lowest age bracket ended up facing one another
every single match. In the case of 116, that meant all 8 qualification matches were against 122. 116's middle bracket opponents in one match would be their middle bracket partners in their next match (in graduating numerical order). This is obviously unacceptable.
While FIRST and the algorithm designers rectified the most egregious of those errors as the season progressed, both the fundamental concept aned execution were still flawed. While the practice match schedules from Championship 2007 don't exist explicitly, you can determine them by looking at the first few matches on any given teams' qualification schedule (they were identical, albeit with filler line teams as necessary). That's both an execution and a conceptual issue. While the best of the best teams could often overcome the biased schedules, the rankings were rather skewed that season. Younger teams capable of executing the game had a distinct advantage. As a result, you saw a number of "weaker" alliance captains. 1712 was not a top 8 robot on Galileo that season, but being a sophomore team capable of scoring consistently gave 1712 a very favorable schedule when matched against predominantly other second and third year teams. This is a conceptual flaw.
Regardless of how you determine team skill, whether it be age, OPR, district points, or some other metric, attempting to create a biased schedule creates inequality. When you create a metric-based strength of schedule constraint on the scheduling algorithm, it ends up creating additional reward for teams who outperform their previous metric (and implicitly punishing teams unfortunate enough to draw them). The same applies in reverse to teams that underperform their metrics. Think of how a rookie star like 5985 or 5817 would fit into such a system, and the impact they would have on scheduling. Think of how a powerhouse team that lost key mentors would impact the system.
An example of this is looking at the
OPR for 2007 Galileo. Every team in the top 15 was a member of the highest numbered (youngest) bin. While the exponential scoring on 2007 makes OPR essentially useless for that game, this demonstrates the scheduling bias in play (and also demonstrates how introducing a strength of schedule constraint ends up invalidating the metrics you're using to create the strength of schedule).
More importantly, once you start adding additional constraints to the schedule, you have to be more flexible on the existing constraints. That was one of the huge issues with the 2007 algorithm, and is a fundamental problem with any attempt at adding a strength of schedule constraint. When you factor in strength of schedule, suddenly you have to be more willing to flex on one or more of the other constraints (minimum time between matches, round parity, minimum schedule repeats, etc). While the execution of the 2007 scheduling algorithm was tremendously poor in this respect (namely in terms of minimizing repeats), it's not purely an execution issue.